The primary objective of this work is to create routinely useful techniques for spin-echo-based, three-dimensional (3D), single-slab magnetic resonance imaging (MRI) of the human brain in clinically reasonable times. The comprehensive, high-resolution coverage accomplished with these new sequences will provide more complete descriptions of pathological components of brain diseases, higher probabilities of detecting focal abnormalities, and more accurate, quantitative evaluations of the extent of lesions. The new methods have not been feasible before now because of performance limitations of the gradient subsystems on MR imagers. The advent of high- performance gradient subsystems has created this opportunity for SE-based 3D, single-slab acquisitions. The research aims to: (1) refine the design of the new pulse sequence architectures, (2) examine their contrast and artifact behaviors, (3) address image artifacts arising from the gradient system's performance, (4) implement the sequences on an imager in a research setting and optimize the design, and (5) demonstrate in a clinical setting that the new techniques yield higher resolution, and contrast and artifacts at least comparable to current 2D SE-based techniques. Generally, the proposed work is a necessary series of tests and refinements of new pulse sequences and new equipment, culminating in a clinical assessment of brain lesions in patients who have multiple sclerosis. The series progresses from theoretical studies to experimental imaging of phantoms and healthy volunteers to patient studies. The major challenge is to resolve issues related to the contrast and artifact features of the sequences and the gradient system's performance. A powerful technique for acquiring three-dimensional images of the human brain will result from this research. Because of its high spatial resolution, the technique will be important for diagnostic neuroimaging, and highly useful for quantitative assessment of tissue volumes in the brain. The latter outcome will provide improved objective assessment of changes in brain tissue over the course of therapeutic trials. Furthermore, the proposed technique, when implemented, will supply a tool with new capabilities for MRI-based research into the pathogenesis of disseminated diseases of the brain.